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wire TATES FFIQEQ PATENT TELEGRAPH-RECEIVER.

5PECIPICA'IION forming part of Letters Patent No. 388,092, dated August21, 1888.

Application filed December 27, 1887. Serial No. 259,105. (No model.)

To all whom, it may concern.-

Be it known that I, FRANQOIS VAN RYssEL- BERGHE, a subject of the Kingof Belgium, and a resident of Brussels, Belgium, have invented certainnew and useful Improvements in Telegraph-Receivers, of which thefollowing is a specification.

My invention relates to tone or harmonic telegraphy, and more especiallyto apparatus designed for use as receivers in connection with suchsystems, and more particularly in connection with such a system as isdescribed and patented to me in United States Patent No. 370,577.

In the use of such systems of telegraphy, especially when it is desiredto employ but a single-line circuit for the transmission ofalarge numberof messages, it is desirable, and indeed necessary, to have verydelicate and at the same time positively-acting instruments to serve asreceivers, it being understood that each receiver is intended to respondto one only of a number of transmitters which may be snperposing on orsending over the same main line varying series of electric impulses orchanges of electric potential at the same time.

I make use of a single electromaguet, constructed and arrangedsubstantially as hereinafter set forth, and illustrated in theaccompanying drawings, which show a perspective view of areceivinginstrumcnt made in accordance with my invention, and which isarranged to control and operate all the receiving-instruments at thatend of the line.

A series of tuning-forks, 1 2 3 4 5 6 7 S, are mounted upon a frame, 9,which is preferably of soft iron, and which is bent as shown in thedrawings, and the free ends or tines of these forks extend inward, andprojecting between these ends is a core, 10, which is also mounted uponand forms part of the frame 9. Surrounding this core is the line-wirecoil 11, and itwill thus be seen that when the frame is of soft iron thewhole constitutes an electromagnet in which the core forms one pole andthe tuningforks the other pole, and in this way the forks aremagnetized. In order, however, that the forks may be maintained in amagnetic condition independent of the currentof the line-circuit and'apermanent magnetic field may be created between the free ends of thefork and the common core-piece10,I preferably apply an additional coil,12, to the core, which is connected up with a local-battery circuit, 15.It will be understood, of course, that when the receivinginstrument istobe used in a duplex or quadruplex system the magnet will bedifferentially woundin the usual way. It will thus be seen that all thetuning-forks are operated by a single electro-magnet having a corecommon to all the forks, and while it is true that each fork will beaffected by a part only of the energy of the line-current, I have foundby actual experiment that the use of a single electro-magnet controllingthe whole set of receivers gives much better results than when there isascparate electro-magnet for each receiving-instrument.

Of course it is understood that each tuningfork will be tuned oradjusted so as to have a certain definite or fundamental rate ofvibration and to be operated only by variations in the electricpotential of the line-circuit corresponding to such rate,and whichvariations are caused by suitable transmitting devices tuned or adjustedin accordance with the various forks; and in order to construct andadapt the forks to have such variations in funda mental tones, I maymake use of any of the well-known characteristics of the forks whichcontrol the rate of vibration. In the instance shown all the forks havea common base-piece, 16, which is attached to the arm 1-1- of the frame9, and this frame may be so arranged that the length of the forks willvary in proper relative proportion to produce the various fundamentaltones; or the legs or tines of the respective forks may be of differentweights, so that they will have the proper fundamental tone.

Vhile the forks themselves may be used as receivirig-instruments, inpractice I preferably utilize the forks to operate some localreceivinginstrnment to intensify the signals received by the forks, andI preferably make use of a local circuit includinga telephone, asindicated in dotted lines, and arranged so as to be operated by thefork, substantially in the manner set forth in my application,Serial No.255,252, filed November 15, 1887; but it will be understood that anyother intensifier may be used.

From the above arrangement it will be seen that I am enabled to reducethe expense of constructing the numerous receivirig-instruments,

lic frame having upon one end an extended core-piece, a mainline coilsurrounding said core-piece, and a series of tuning-forks having varyingfundamental rates of vibration, arranged upon the other end of the frameand extending into proximity with the core-piece, substantially asdescribed.

2. In a tone or harmonic telegraph, a receiving-instrument having asingle electromagnet and core therefor, and a series of tuning-forksarranged to be operated by said magnet, and a local battery and coilconnected therewith surrounding said core, substantially as described. 7

3. In a tone or harmonic telegraph, a receiving-instrument consisting ofa bent magnetized frame, a series of forks secured to and constitutingone pole of the frame, and a corepiece secured to and constituting theother pole of the frame and controlling all the forks, substantially asdescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

FRANQOIS VAN RYSS'ELBERGHE. Witnesses:

A. OoRMAND, ADOLF STEINE.

